Our results show that maturation of line acuity is still taking place between the ages of 4 and 9 years. Measured acuity is affected by the amount of contour interaction induced by the type of optotype (letter or picture) and by the interoptotype separation. Another factor, probably a maturation of gaze control or selective attention is responsible for the reduction in crowding with age.

We used custom-designed acuity tests to compare the magnitude and extent of crowded letter recognition in children and adults. Visual acuity (logMAR) was measured monocularly in children and adults using five custom-designed letter tests with varying degrees of crowding: single letter, single letter surrounded by four flanking bars, single letter surrounded by four flanking letters, line of five letters surrounded by flanking bars, and line of five letters surrounded by flanking letters. The tests were constructed using Sloan letters and presented on an iPad (Apple Incorporated, Cupertino, CA) at 4 m using a standardized endpoint and instructions. Crowded logMAR was normalized to unflanked logMAR and results were analyzed in three groups: younger children aged 4-6 (n = 32), older children, aged 7-9 (n = 30), and adults (n = 27). Both groups of children showed a greater extent of crowding than the adults. The adult participants showed no difference in performance between single or linear presentation and letter or bar flankers. Letter flankers and linear presentation individually resulted in poorer performance in the younger children p < 0.001 and p = 0.003, respectively (mean normalized logMAR 0.17 in each case) and together had an additive effect (mean 0.24), p < 0.001. Crowding in the older children was adult-like except in the linear presentation with letter flankers, p < 0.001. These results indicate that both target-flanker similarity and linear presentation contribute more to foveal crowding in young children than in adults.

Purpose: Lid wiper epitheliopathy (LWE) is a clinical sign that has been associated with dry eye disease. This study used a semi-automated method to identify the effect of drop instillation and post-dye viewing time on the absorption of lissamine green (LG) and sodium fluorescein (NaFl) on the upper eyelid in order to ascertain the optimal identification for LWE assessment. Methods:In 37 participants with LWE, 1-drop of 1% LG (10μL) was applied to the superior bulbar conjunctiva in the right eye, and photographs of the lid margin were taken 1, 3, and 5 minutes after instillation. Measurements were repeated in the same eye following instillations of 2-drops of 1% LG. The same procedures were followed for application of 2% NaFl (2μL) to the left eye. Staining area was determined using software to detect and measure dye-stained images. Analysis used a linear mixed model with fixed effects of time, number of drops and their interaction.Results: For LG, multivariate analysis showed that time of drop instillation was significant (p=0.0091) as was the area of staining in the 2-drop versus 1-drop condition (p<0.0001).For NaFl, there was a significant effect of time (p<0.0001), drops (p<0.0001), and a time/drops interaction (p<0.0134), suggesting that both time and number of drops are important. Conclusion:A single drop of dye is insufficient to reveal the full extent of LWE staining.A 2-drop instillation is recommended and observation is recommended between 1-5 minutes (LG) and between 3-5 minutes (NaFl).

Purpose In late 2019, a new coronavirus capable of infecting humans, SARS‐CoV‐2, was identified in Wuhan, China. The resultant respiratory disease was subsequently named COVID‐19. In March 2020, in response to the COVID‐19 pandemic, primary care optometry practices only remained open to deliver essential or emergency eye care. This study aimed to characterise the experiences of United Kingdom (UK)‐based primary care optometrists during the COVID‐19 pandemic. Methods An email invitation to participate in an online cross‐sectional survey was sent to 3000 UK‐based, currently practicing members of The College of Optometrists (UK). Responses to the structured questionnaire were analysed using descriptive statistics, including frequencies, means and standard deviations. Frequency analyses were used to evaluate items with multiple responses. Free‐text responses were examined using thematic analyses. Results After data cleaning, a total of 1250 responses remained. Sixty‐three percent were female, 70% self‐identified as being of white ethnicity and 78% were based in England. During the first national lockdown, over half of all respondents were involved with the provision of remote consultations for emergency/urgent care. The majority felt ‘very’/‘moderately’ comfortable conducting remote consultations, but 66% felt professional liability was increased. Forty percent were involved in the provision of face‐to‐face consultations. Eye‐health and vision‐related problems were the most commonly reported patient issues during both remote and face‐to‐face consultations, while contact‐lens related problems were the least. Thematic analysis of the responses showed several challenges adjusting to the pandemic (e.g., working safely), but also some potential benefits (e.g., increased skills). Conclusions The findings provide an overview of changes to optometric practice in the UK during the COVID‐19 pandemic. The results may be used to inform the development of professional guidance and facilitate resource allocation for safe and effective eye care during this and any future pandemics.

Foveal vision in strabismic amblyopia can show increased levels of crowding, akin to typical peripheral vision. Target-flanker similarity and visual-acuity test configuration may cause the magnitude of crowding to vary in strabismic amblyopia. We used custom-designed visual acuity tests to investigate crowding in observers with strabismic amblyopia. LogMAR was measured monocularly in both eyes of 11 adults with strabismic or mixed strabismic/anisometropic amblyopia using custom-designed letter tests. The tests used single-letter and linear formats with either bar or letter flankers to introduce crowding. Tests were presented monocularly on a high-resolution display at a test distance of 4 m, using standardized instructions. For each condition, five letters of each size were shown; testing continued until three letters of a given size were named incorrectly. Uncrowded logMAR was subtracted from logMAR in each of the crowded tests to highlight the crowding effect. Repeated-measures ANOVA showed that letter flankers and linear presentation individually resulted in poorer performance in the amblyopic eyes (respectively, mean normalized logMAR = 0.29, SE = 0.07, mean normalized logMAR = 0.27, SE = 0.07; p < 0.05) and together had an additive effect (mean = 0.42, SE = 0.09, p < 0.001). There was no difference across the tests in the fellow eyes (p > 0.05). Both linear presentation and letter rather than bar flankers increase crowding in the amblyopic eyes of people with strabismic amblyopia. These results suggest the influence of more than one mechanism contributing to crowding in linear visual-acuity charts with letter flankers.